Re: [gtk-list] Re: Should there be a gtk "canvas" widget?

[Tom Tromey <tromey creche cygnus com>]

Marius> What about implementing the PDF primitives as basic canvas
Marius> objects.  Does X11 allow for efficient, filled, clipped,
Marius> bezier curves?

No.

Tk has a spline implementation you could probably steal.

Marius> Can we afford to always have a backing pixmap for the whole
Marius> image?  If not, how can we get flicker free updates?  How does
Marius> Tk handle this?

Tk widgets generally do use a temporary backing pixmap.  However, the
canvas only makes a pixmap for the part that needs to be refreshed.
Canvas items are required to be a little smart about refreshing (they
have to know that they have to do a coordinate transform before
drawing).

If you have a Tk distribution around, look at the "CrtItemType.3" man
page.  It describes how to write a new canvas item for Tk.

Tk canvases can also generate a PostScript representation of their
contents.  Dunno if that's worth reproducing (I've certainly used it
in the past...).

Tom